Carbon-13 Nuclear Magnetic Resonance Spectroscopy: Carbon-13 Chemical Shifts and Coupling Constants

摘要: Publisher Summary This chapter deals with the chemical-shift correlations within different classes of organic compounds and also focuses on 13 C coupling constants. The developments in instrumentation measurement techniques that may be utilized for NMR are discussed chapter. In order to overcome low natural abundance sensitivity isotope, large sample tubes high values r.f. power have generally been used observe resonance signals. Flow avoid difficulties from saturation improved can achieved, by using internuclear double technique (INDOR). Enhancement signals obtained, examining presence free radicals. Proton-decoupling techniques, addition increasing signal intensity collapse C– 1 H coupling, give rise overhauser enhancement. Later, theoretical considerations provided carbon-13 chemical shifts nuclear spin-spin involving carbon-13. simple unsubstituted hydrocarbons predicted, additivity relations, although there serious deviations constitutive rule when substituted polar groupings. alicyclic provides information regarding conformational preference rings.